Casse are completely remade into the Pritanoi, which is essentially the same. From the looks of it there will be an Lugii faction which are Celto-Germanic I think and the Belgae will probably make it in as well.

Not sure that proces was with Areus, he simply rebelled against the Macedonians(an war but considering Macedons power its more an rebellion). You're right about Agis and Kleomenes but I think they came way later then start of the game. I agree though, having an Spartan, achean or aetolian faction would probably be better.